Patent Document 1 (Japanese Patent Application Laid-Open (JP-A) No. 2015-054644) discloses, in a vehicle lower portion structure that has brackets that fix seats, a structure in which the bottom portion of a bracket is fixed to the floor panel, and the side portion of the bracket is fixed to the side wall of the tunnel portion or the side wall of a rocker (side sill). Note that the structure disclosed in Patent Document 2 (JP-A No. 2012-166710) exists as a vehicle floor structure that is equipped with an on-tunnel reinforcement on the upper portion of the tunnel portion.
In the structure disclosed in aforementioned Patent Document 1 (JP-A No. 2015-054644), the bottom portion of the bracket is fixed to the floor panel, and the seat is fixed by the brackets. In this structure, there is the possibility that stress may concentrate at the joined portions (the fixed places) of the brackets and the floor panel in a case in which load from the passenger is transmitted to the brackets at the time of a front collision, as compared with, for example, a structure in which the brackets are provided on a cross member that is bridged between the tunnel portion and a rocker.
In view of the above-described circumstances, an object of the present invention is to provide a vehicle floor portion structure that can suppress a concentration of stress at the joined portion of a bracket and a floor panel at the time of a front collision of a vehicle.